On behalf of the ATLAS and CMS Collaborations

Transcription

1 On behalf of the ATLAS and CMS Collaborations Reza Goldouzian Université libre de Bruxelles 1

2 Ø There are several models of physics beyond the standard model require new particles that couple to quarks and/or gluons and decay to dijets or dileptons Ø Extra dimensions, compositeness, QBH, Ø Di-jet and di-lepton final states are classic signatures to search for New physics Experimental signature: bump over a continuous background 2 Channel Search ATLAS CMS Dijet Dilepton High mass di-jet resonance Phys. Rev. D 96, (2017) CMS-EXO Low mass di-jet resonance EXOT CMS-EXO B-tagged di-jet resonance ATLAS-CONF CMS-EXO Boosted di-jet resonance EXOT JHEP 01 (2018) 097 χ of di-jet Phys. Rev. D 96, (2017) CMS-EXO High mass di-electron + di-muon resonance JHEP (2017) 182 CMS-EXO , CMS-EXO High mass eµ resonance Eur. Phys. J. C76 (2016) 541 CMS-EXO

3 3 Phys. Rev. D 96, (2017) data: s = 13 TeV, L = fb 1 (ATLAS) Ø Trigger: single jet p T > 380 GeV Ø At least two jets with p leading T > 440 GeV and p subleading T > 60 GeV Ø Forward QCD background events are reduced using y* = (y 1 -y 2 ) cut 8.1 TeV Ø Resonance selection: y* <0.6, m jj > 1.1 TeV Ø W* selection: y* <1.2, m jj >1.7 TeV Ø QCD background smoothly falling Ø Background Estimate: Sliding Window Fit (new) Ø No significant excess observed

4 4 Ø Limits on various BSM models Ø Model Independent Resonance (Gaussian) Ø New folding technique applied (factorized out detector effects) σ A BR [pb] 1 1 Exp. 95% CL upper limit for σ G /m G = 0 Expected ± 1 σ and ± 2 σ Obs. 95% CL upper limit for: σ G /m G = 0.15 σ G /m G = 0. σ G /m G = 0.07 σ G /m G = 0.03 σ G /m G = 0 Ø Limits on a range of masses and couplings of a Z dark matter mediator model q g ATLAS s = 13 TeV, 37.0 fb -1 Observed 95% CL upper limit Expected 95% CL upper limit y* < s=13 TeV, 37.0 fb ATLAS m G [TeV] m Z' [TeV]

5 5 CMS-EXO data: s = 13 TeV, L = 36 fb 1 (CMS) Ø Trigger: H T > 800 GeV (H T :scalar sum of all jets with p T >30 GeV and η <3) Ø Selection: p T jet >30 GeV, η <3 and M jj > 1.25 TeV Ø close jets are combined into wide jets to calculate the dijet mass Ø Designed to reduce the analysis sensitivity to gluon radiation from final-state partons Ø QCD background smoothly falling Ø Global background fit used Ø No significant excess observed

6 6 Ø Limits on various BSM models Ø Limits on a range of masses and couplings of a Z dark matter mediator model

7 7 CMS-EXO , ATLAS-CONF data: s = 13 TeV, L = 27 fb 1 (CMS) Ø Data scouting: Reconstruct/save only necessary information Ø Calo scouting: Ak4 calo jets ATLAS results will be presented in Carl s talk Ø Selection: p T jet >30 GeV, η <3 and M jj > 0.49 TeV Ø No evidence for dijet resonance Lowest unprescaled HLT

8 8 ATLAS-CONF data: s = 13 TeV, L = 13.3 fb 1 (ATLAS) Ø High mass resonance search with one or two b-jets Ø No significant excess observed and b* excluded below 2.3 TeV Ø Limits on generic Gaussian shapes

9 9 CMS-EXO data: s = 8 TeV, L = 19.7 fb 1 (CMS) Ø High mass resonance search with two b-jets Ø Two signal regions due to the trigger requirement Ø SR1: m jj =[296-58] Ø SR2: m jj =[ ] Ø No significant excess observed

10 EXOT , JHEP 01 (2018) data: s = 13 TeV, L = 36 fb 1 (ATLAS), L = 35.9 fb 1 (CMS) Ø Boosted dijets + associated ISR jet/photon Ø Limits are set on the parameter space of a lepto-phobic axial-vector Z benchmark model ATLAS results are presented in Dermot s talk

11 11 Phys. Rev. D 96, (2017), JHEP 01 (2018) data: s = 13 TeV, L = 37 fb 1 (ATLAS), L = 35.9 fb 1 (CMS) Ø QCD ~ flat, look for rise at low χ, high m jj Ø Can search for non-resonant new physics 1/N dn/dχ < 56m jj < 5.4 TeV < m jj < 4.9 TeV χ s=13 TeV, 37.0 fb m jj > 5.4 TeV ATLAS Data SM CI η = 1, Λ=22 TeV LL CI η =+1, Λ=15 TeV LL Theoretical uncert. Total uncertainty < 5 6m 7 jj < 4.6 TeV < 5 6m 7 jj < 4.3 TeV χ χ < 5 6m 7 jj < 4.0 TeV < m jj < 3.7 TeV χ χ

12 12 JHEP (2017) 182, CMS-EXO , 2016 data: s = 13 TeV, L = 36.1 fb 1 (ATLAS), 35.9 fb 1 (CMS) Ø Lepton resonances: clean signature with low backgrounds Ø Events with two same-flavor leptons (e/µ) are selected Ø No significant excess observed

13 13 Ø Limits on Ø The mass and couplings of various Z gauge bosons Ø The mass of a mediator boson and of a DM particle in a simplified model

14 14 CMS-EXO data: s = 13 TeV, L = 41.4 fb 1 (CMS) Ø Search strategy: similar to 2016 [σ.b] Z' / [σ.b] Z 5 6 CMS Preliminary fb (13 TeV, ee) Observed 95% CL limit Expected 95% CL limit, median Expected 95% CL limit, 1 s.d. Expected 95% CL limit, 2 s.d. Z' SSM Ø Challenge: new CMS pixel detector Ø Electron channel only 7 Z' ψ Ø Data is consistent with backgrounds M [GeV] Ø No evidence for a significant deviation Ø The 2017 data is combined with 2016 dataset to increase the search sensitivity [σ.b] Z' / [σ.b] Z 5 6 CMS Preliminary fb (13 TeV, ee) fb (13 TeV, µ + µ ) Observed 95% CL limit Expected 95% CL limit, median Expected 95% CL limit, 1 s.d. Expected 95% CL limit, 2 s.d. Z' SSM Z' ψ M [GeV]

15 15 Ø The Run 2 high mass di-jet and di-lepton resonance searches at the LHC are performed Ø Complementary approaches at low mass di-jet searches are employed: reduced event size, trigger on ISR, dedicated b-jet triggers Ø Observations are in agreement with standard model expectations Ø Upper limits on the product of a new resonance production cross section and branching fraction to di-jets/dileptons are calculated in a model-independent manner Ø Limits are interpreted to constrain parameters of models predicting a narrow di-jet or di-lepton resonance q CMS Preliminary Moriond % CL exclusions g' 1 Γ Z' / M Z' =0% Γ Z' / M Z' =50% Γ Z' / M Z' =30% Γ Z' / M Z' =% Γ Z' / M Z' =5% Γ Z' / M Z' < ~0% CMS Dijet χ, 13 TeV [EXO ] Γ Z' / M Z' < ~% ATLAS Boosted Dijet, 13 TeV [arxiv: ] ATLAS Dijet, 13 TeV [arxiv: ] ATLAS TLA, 13 TeV [ATLAS-CONF ] Updates for ATLAS results in Carl s and Dermot s talks CMS Dijet, 13 TeV [EXO ] ATLAS Dijet+ISR γ, 13 TeV [ATLAS-CONF ] 1 Z' qq CMS Dijet, 8 TeV [arxiv: ] CMS Dijet b tagged, 8 TeV [arxiv: ] CMS Boosted Dijet, 13 TeV [arxiv: ] ATLAS Dijet+ISR j, 13 TeV [ATLAS-CONF ] UA2 [Nucl. Phys. B 400, 3 (1993)] CDF Run1 [arxiv:hep-ex/ ] M Z' [GeV] CDF Run2 [arxiv: ] Z width (all Γ Z' /M Z' ) [arxiv: ]